Add auto-advance: click Next, scroll to top, capture next page

After each capture the controller asks the vision model to locate a 'Next'
control (returned as normalized screen coordinates), clicks it via OS input,
scrolls to top, and continues the loop. Configurable via SCREEN_LEADS_AUTO_NEXT
/ _NEXT_LOAD_PAUSE / _MAX_AUTO_NEXT, with a per-run safety cap.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

dashboard/support.html

@@ -147,6 +147,9 @@ python main.py</code></pre>
     <tr><td><code>ANTHROPIC_API_KEY</code></td><td>—</td><td>Required. Claude API key.</td></tr>
     <tr><td><code>SCREEN_LEADS_MODEL</code></td><td>claude-opus-4-8</td><td>Vision model (use claude-sonnet-5 to cut cost).</td></tr>
     <tr><td><code>SCREEN_LEADS_START_DELAY</code></td><td>5</td><td>Grace seconds before first capture (0 = off).</td></tr>
+    <tr><td><code>SCREEN_LEADS_AUTO_NEXT</code></td><td>true</td><td>After each capture, click a "Next" control, scroll to top, and continue.</td></tr>
+    <tr><td><code>SCREEN_LEADS_NEXT_LOAD_PAUSE</code></td><td>2.5</td><td>Seconds to wait for the next page to load after clicking Next.</td></tr>
+    <tr><td><code>SCREEN_LEADS_MAX_AUTO_NEXT</code></td><td>25</td><td>Safety cap on auto-advances per run.</td></tr>
     <tr><td><code>SCREEN_LEADS_SCROLL_STEPS</code></td><td>6</td><td>Screenshots per profile.</td></tr>
     <tr><td><code>SCREEN_LEADS_SCROLL_AMOUNT</code></td><td>800</td><td>Scroll distance per step.</td></tr>
     <tr><td><code>SCREEN_LEADS_SCROLL_PAUSE</code></td><td>0.8</td><td>Settle time (s) after each scroll.</td></tr>